The present invention relates to a fastener driving tool such as a nail gun driven by compressed air, and more particularly, to an arrangement that avoids accidental release of a head bumper.
Generally, in a conventional pneumatically operated fastener driving tool, a piston slidably movable in a cylinder is pneumatically driven to its bottom dead center for driving a faster into a workpiece. The piston strikes against a bumper disposed at a lower end of a cylinder, and further, the piston strikes against a head bumper positioned above the cylinder during upward moving stroke of the piston. These bumpers are formed of an elastic material for absorbing shock imparted by the piston. Such arrangement is disclosed in, for example, laid-open Japanese Patent Application Kokai No. 2001-162557.
Conventionally, the head bumper is axially compressedly and concentrically fitted over a shaft protruding downwardly from a top wall region of a main housing. A release of the head bumper from the shaft has been recognized.